Application of Landsat‐7 satellite data and a DEM for the quantification of thermokarst‐affected terrain types in the periglacial Lena–Anabar coastal lowland

• Published in: Polar Research
• Main Authors: Grosse, Guido, Schirrmeister, Lutz, Malthus, Timothy J
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Norwegian Polar Institute 2006
• Subjects: Climate change; Ice; laptev; Laptev Sea; permafrost; Polar Research; Thermokarst
• Online Access: https://epic.awi.de/id/eprint/57871/; https://epic.awi.de/id/eprint/57871/1/Grosse_2006_PolRes.pdf; https://hdl.handle.net/10013/epic.841b7a1b-b37d-4f85-bcc4-17a1249096b7

Extensive parts of Arctic permafrost-dominated lowlands were affected by large-scale permafrost degradation, mainly through Holocene thermokarst activity. The effect of thermokarst is nowadays observed in most periglacial lowlands of the Arctic. Since permafrost degradation is a consequence as well as a significant factor of global climate change, it is necessary to develop efficient methods for the quantification of its past and current magnitude. We developed a procedure for the quantification of periglacial lowland terrain types with a focus on degradation features and applied it to the Cape Mamontov Klyk area in the western Laptev Sea region. Our terrain classification approach was based on a combination of geospatial datasets, including a supervised maximum likelihood classification applied to Landsat-7 ETM+ data and digital elevation data. Thirteen final terrain surface classes were extracted and subsequently characterized in terms of relevance to thermokarst and degradation of ice-rich deposits. 78 % of the investigated area was estimated to be affected by permafrost degradation. The overall classification accuracy was 79 %. Thermokarst did not develop evenly on the coastal plain, as indicated by the increasingly dense coverage of thermokarst-related areas from south to north. This regionally focused procedure can be extended to other areas to provide the highly detailed periglacial terrain mapping capabilities currently lacking in global-scale permafrost datasets.